The Nernst equation is one of the two central equations in electrochemistry. It describes the dependency of an electrode’s potential E and the activities a or simplified concentrations c of the redox reaction’s species.
The Nernst Equation
The remaining parameters in the equation are the universal gas constant R, the temperature T, the Faraday constant F, the standard potential of the reaction Ox to Red E^{0} and the number of transferred electrons per molecule z.
It is more common to use the simplified version:
simplified Nernst Equation
As a new parameter the formal potential E^{0′} is introduced, which includes the influence of the activity coefficients.
Important for an electrochemist to understand that this equation works in two ways. If the electrodes potential is changed, the solution in contact with the electrode needs to have the concentration ratio of active species indicated by the Nernst equation. To achieve this an electrochemical reaction needs to take place at the electrode.
More information is available in this article.
In this section the reasons for the three electrode setup of most potentiostats is explained, what the task of each electrode is and what to take into consideration when choosing your counter electrode. What Is a Potentiostat Good for? A voltmeter does measure the potential difference between two points. To do so the circuit needs …
This section is a short explanation of the processes that lead to electrochemical potential and thus to corrosion processes. Most readers will have a rough idea of electrochemical potentials, noble and non-noble metals. However, a small recap of this knowledge seems suitable to understand the processes happening at the electrodes or corroding metals better. If …
There is sometimes confusion about the option to measure versus Ecorr / OCP and versus the reference electrode. In this section the reasons for choosing a certain DC potential is explained. The advantages of using Ecorr as a reference point will be presented as well as how to choose in PSTrace to use potentials versus …